Venturi system for conveying flexible fabrics

ABSTRACT

A venturi incorporated in a pneumatic tube conveying system for flexible textile fabrics such as uniform and table linens handled in commercial laundries. The venturi includes an angled pipe which joins the main piping system at an acute angle and which receives air from a blower. An inside pipe is installed within the main piping to create a restriction at the connection of the venturi with the main piping. The restriction and angled connection of the venturi pipe creates a low pressure area which draws fabric articles through the piping and discharges them directly into receptacles such as sling carts. A screened vent in the piping downstream from the venturi allows the escape of air to enhance the reliability and efficiency of the pneumatic conveying system. The exposure of the vent can be adjusted by a sleeve that slides back and forth on the conveyor tube at the location of the vent.

FIELD OF THE INVENTION

[0001] This invention relates generally to the pneumatic conveying offlexible fabrics such as uniforms, table linens and other articleshandled by commercial laundries, as well as other fabric items that areconveyed between different locations in other types of applications.More particularly, the invention is directed to a method and apparatusthat makes use of a specially constructed venturi to provide a suctionforce for pulling fabrics through conveyor tubes.

BACKGROUND OF THE INVENTION

[0002] Commercial laundries handle large volumes of a variety ofmaterials, including table cloths, napkins and other table linens usedin restaurants and other food service operations. Uniforms worn by fastfood service personnel and others are examples of other types ofarticles that are typically laundered by commercial laundries. Asignificant part of the operation of commercial laundries involvessorting the different types of articles while keeping track of wherethey came from and the number and types of articles that are to belaundered.

[0003] Typically, the items are sorted at a sorting table or othersorting station. Like articles are then conveyed pneumatically toanother location where they are further handled. Because flexiblefabrics tend to ball up when pushed through pneumatic conveyor tubes,they are usually pulled through the tubing system by suction. The typeof system that is most prevalent in commercial laundries makes use ofvacuum bins that are each provided with a large vacuum motor. The vacuumthat is applied to the vacuum bins pulls the laundry items through theconveyor tubes and into the bins.

[0004] Although vacuum bins of this type have achieved considerablepopularity, they have not been satisfactory in all respects. Theirrelatively high cost adds appreciably to the capital costs of thelaundry equipment. Furthermore, it is necessary for the items in thevacuum bins to be manually unloaded and placed on a conveyor whichcarries them to the location of receptacles that are typically flexiblecarts commonly referred to as sling carts. The articles must then bemanually unloaded from the conveyor and placed in the sling carts. Ascan easily be appreciated, the need for all of these manual operationsadds significantly to the overall labor costs. Finally, the vacuum binsand conveyors that transport articles from the bins to the sling cartsoccupy considerable space. This is particularly unsatisfactory in thecase of commercial laundries because they are usually located in highcost urban areas where they are close to their major customers.

SUMMARY OF THE INVENTION

[0005] The present invention is directed to a method and apparatus forconveying flexible fabric articles in an improved way that avoids theshortcomings of vacuum bin systems. In particular, the present inventionprovides a venturi system that dramatically reduces the equipment costs,labor costs and space requirements compared to vacuum bin systems.

[0006] In accordance with the invention, a uniquely arranged venturistructure is provided for applying a suction force at a selectedlocation along the conveyor tube system rather than at its discharge endas is necessary with a vacuum bin system. Because the venturi is locatedalong the conveyor tubing, the tubing can discharge the fabric itemsdirectly into sling carts or other receptacles, thus eliminating thespace occupied by the vacuum bins and the intermediate conveying systemas well as the labor that is required to manually unload the articlesfrom the vacuum bins and to later load them into the sling carts.

[0007] The venturi system of the present invention preferably includesan angled pipe which joins the conveyor tubing at an acute angle and issupplied with air by a blower. An inside pipe is located within thetubing at its juncture with the angled venturi pipe in order to providea restriction that creates a low pressure area in the conveyor tubing.The resulting suction force draws the fabric articles to the area of theventuri and thereafter transports them a relatively short distance tothe discharge end of the conveyor tubing by the positive force suppliedby the blower. At the discharge end of the tubing, the fabric articlesare discharged directly into receptacles such as sling carts.

[0008] An important feature of the invention is the provision of a ventin the conveyor tubing at a location downstream from the venturi. Thevent is preferably a screened gap in the tubing which allows a portionof the air to escape. The vent significantly enhances the smoothness andreliability of the conveyor system by partially relieving the airpressure and thereby suppressing pressure fluctuations and otherunfavorable pressure conditions that can adversely affect operation ofthe conveyor system. An adjustable sleeve in the preferred embodiment ofthe invention allows the width of the gap to be adjusted as necessary.

[0009] Other and further objects of the invention, together with thefeatures of novelty appurtenant thereto, will appear in the course ofthe following description.

DESCRIPTION OF THE DRAWINGS

[0010] In the accompanying drawings which form a part of thespecification and are to be read in conjunction therewith and in whichlike reference numerals are used to indicate like parts in the variousviews:

[0011]FIG. 1 is a diagrammatic view of a pneumatic conveyor tubingsystem that is equipped with a venturi arrangement constructed accordingto a preferred embodiment of the present invention and used to conveyflexible fabrics from a sorting table or other sorting station toreceptacles such as sling carts; and

[0012]FIG. 2 is a fragmentary sectional view on an enlarged scaleshowing the venturi system and the adjacent portions of the conveyortubing.

DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention is directed to a method and apparatus forthe pneumatic conveying of fabric materials such as table linens (tablecloths, napkins and the like), uniforms, and other articles that aretypically laundered in commercial laundries, as well as other flexiblefabrics that are pneumatically conveyed in other applications. FIG. 1illustrates diagrammatically a pneumatic conveying system of the typethat may be installed in a commercial laundry facility. A sorting tablegenerally identified by numeral 10 or a similar sorting station is usedfor the sorting of articles and may be equipped with a back panel 12having a transparent window 14. Pneumatic conveyor tubing generallyidentified by numeral 16 extends from the back of the table and islocated for the most part at an overhead location, although otherlocations are possible.

[0014] An opening 18 in the panel 12 may provide an input opening intowhich articles may be fed into a vertical tube 20 which is part of theconveyor tubing 16. An elbow 22 connects the top end of tube 20 with anelevated horizontal conduit 24 which terminates in a substantiallystraight end portion 26. The conduit 24 may have virtually any desiredconfiguration and can include bends and other offsets as may benecessary to avoid obstructions or extend the conveyor tubing to thedesired location. The conduit 24 may incorporate a number of separatetube sections suitably coupled together.

[0015] The end portion 26 of conduit 24 is connected by a coupling 28with a conduit section 30 which has a substantially straight main bodyand a branch leg 32. The leg 32 has an axis that is oriented at an acuteangle to the longitudinal axis of conduit section 30.

[0016] The downstream end of conduit section 30 is connected withanother conduit 34. A vent opening between conduits 30 and 34 isprovided, preferably by a gap 36 that is covered with a mesh screen 38.The ends of conduits 30 and 34 are spaced apart so that the gap 36extends circumferentially around the conveyor tubing. The screen 38covers the entirety of the gap 36 to prevent articles that are beingconveyed from passing out of the conveyor tubing 16 through the gap. Asolid sleeve 39 is fitted closely around the downstream end of conduitsection 30 and is adjustable in a manner to wholly or partially coverthe screen 38 or to not cover the screen at all. The sleeve 39 slidesback and forth in order to vary the size of the gap 36 and thus vary itsexposure.

[0017] The downstream end of conduit 34 is provided with a plurality ofserially arranged fittings 40, 42 and 44. Each fitting 40, 42 and 44 hasa discharge opening 46 which is controlled by a flapper valve 48 orother device. The openings 46 may be located and oriented as desired.The valves 48 are controlled by a suitable control system (not shown)which is not a part of the present invention. Immediately underlying thedischarge openings 46 are respective receptacles 50 which may take theform of sling carts or other types of receptacles or other devices suchas belt conveyors that receive the fabric articles that dischargethrough the openings 36 of the fittings 40, 42 and 44.

[0018] The branch leg 32 forms part of a venturi arrangement constructedaccording to a preferred embodiment of the present invention. A blower52 which may be mounted on the floor or elsewhere is powered by a motor54 and forces air from the discharge side of the blower through pipingthat includes an inclined or angled pipe 56 leading to connection withthe branch leg 32.

[0019] With reference to FIG. 2 in particular, an inside pipe 58 issuitably supported concentrically inside of the conduit section 30 andis positioned to overlie the inlet opening 60 formed at the intersectionof the branch leg 32 with the main body of conduit 30. The inside pipe58 is smaller in diameter than the main body of conduit 30 to provide arestriction 62 adjacent to the downstream end 64 of the inside pipe 58.The restriction 62 is annular and creates a reduced volume regionadjacent to the end 64 in order to provide a low pressure in the conduitsection 30 at the area of the downstream end 64 of the inside pipe 58.The end 64 is spaced downstream from the opening 60 by a distanceidentified by numeral 66 in FIG. 2. By way of example, the conduit endportion 26 may be a six inch diameter pipe, with the main body ofconduit section 30 being an eight inch diameter pipe. The inside pipe 58preferably has approximately the same diameter as the end portion 26, orsix inches in the case where the conduit end portion 26 is a six inchpipe. With these dimensions, the distance 66 is preferably about threeinches, although the distance can vary considerably.

[0020] The inside pipe 58 has an upstream end 68 which is spaceddownstream from the conduit end portion 26 by a distance identified bynumeral 70 in FIG. 2. With the pipe sizes given previously by way ofexample, the distance 70 may be approximately six to seven inches,although this dimension can also vary considerably without adverselyaffecting the operation of the system. Both ends of the inside pipe 58are open so that the fabric articles that are being conveyed through thetubing 16 can pass through pipe section 58. With the pipe sizes given,the length of the inside pipe 58 may be about 24 inches, althoughvariations are possible.

[0021] The screen 36 is preferably cylindrical and is fitted over thedownstream end of conduit section 30 and secured thereon by a band typepipe strap 72 or other suitable means. The screen 38 is fitted aroundthe upstream end of conduit 34 and secured by a band type strap 74 oranother suitable means. Connecting screen 38 in this fashion connectsconduits 30 and 34 to one another. The distance between the downstreamend 64 of the inside pipe 58 and the gap 36 is preferably no less than10 inches and can be considerably greater. The length of the gap 36between the ends of the conduits 30 and 34 may be approximately sixinches, although the length of the gap can vary considerably dependingupon a number of factors, including the sizes of the pipes and blowerand the location of the gap relative to the venturi. The width of thegap 36 can also be adjusted by sliding the sleeve 39 to control itsexposure.

[0022] In operation, the blower 52 operates to force air through theinclined pipe 58 and the branch leg 32 into conduit 30 at therestriction 62. The abrupt change in volume provided by the restriction62 creates a low pressure area adjacent to the downstream end 64 of theinside pipe 58. Fabric articles that are loaded into the conveyor tubing16 are drawn through the conduits 20 and 24 and into the conduit section30 by the suction resulting from the low pressure area, and the articlesare drawn through the inside pipe 58. Downstream from the venturi, thearticles are conveyed to the discharge fittings 40, 42 and 44 by thepositive force of the air supplied by the blower 52.

[0023] The flapper valves 48 are suitably controlled to open a selectedone of the valves 48, such as the valve of fitting 42 as shown inFIG. 1. The articles are then deflected by the flapper valve 48 throughthe discharge opening 46 and into the underlying receptacle 50identified as receptacle #2 in FIG. 1. Different articles are similarlydeposited into the other receptacles 50 by opening the flapper valve 48associated with the corresponding fitting 40 or 44. It should beunderstood that virtually any desired number of discharge fittings canbe provided and that other types of discharge systems can be used inconnection with the pneumatic conveying system.

[0024] The vent effect provided by the gap 36 is an important feature ofthe invention because it allows a portion of the air supplied by theblower 52 to escape from the conveyor tubing 16. The escape of some ofthe air avoids significant pressure fluctuations and other unfavorablepressure conditions in the tubing 16, thereby enhancing the reliabilityof the conveying system and assuring that it operates smoothly.

[0025] The suction effect created by the venturi of the presentinvention is applied at a selected location along the conveyor tubing 16rather than at the discharge end of the tubing as is necessary with avacuum bin system. Consequently, the fabric articles that are beingconveyed can be deposited directly into the receptacles 50, rather thanhaving to be removed from a vacuum bin and separately conveyed to thelocation of the receptacles 50 where an additional manual operation ofdepositing the articles in the receptacles 50 is required. Thus, theventuri system of the present invention is a substantial improvementover a vacuum bin system in a number of respects, namely, theelimination of the high cost of the vacuum bins and the large vacuummotors they require, a reduction in the labor that is required, and areduction in the amount of space occupied by the equipment.

[0026] From the foregoing it will be seen that this invention is onewell adapted to attain all ends and objects hereinabove set forthtogether with the other advantages which are obvious and which areinherent to the structure.

[0027] It will be understood that certain features and subcombinationsare of utility and may be employed without reference to other featuresand subcombinations. This is contemplated by and is within the scope ofthe claims.

[0028] Since many possible embodiments may be made of the inventionwithout departing from the scope thereof, it is to be understood thatall matter herein set forth or shown in the accompanying drawings is tobe interpreted as illustrative, and not in a limiting sense.

Having thus described the invention, what is claimed is:
 1. A system forconveying flexible fabric items such as linens, comprising: a conduithaving an input end for receiving said items and a discharge end fordischarging said items, said conduit providing a substantially enclosedpath for conveying said items from the input end to the discharge end; aselected portion of said conduit having a substantially straight conduitsection presenting a longitudinal axis; an angled pipe connecting withsaid conduit section and having an axis arranged at an acute angle tosaid longitudinal axis; a blower forcing air through said angled pipeand into said conduit section; a restriction in said selected portion ofsaid conduit in proximity to the connection of said angle pipe with saidconduit section to effect a low pressure area adjacent said restrictionwhen air is forced through said angled pipe into said conduit section,thereby drawing air through said conduit to convey said items from saidinput end to said discharge end; and a vent in said conduit at alocation downstream from said restriction for allowing escape of airfrom the conduit between said restriction and said discharge end.
 2. Asystem as set forth in claim 1, wherein said vent comprises a gap insaid conduit extending substantially continuously around the conduit. 3.A system as set forth in claim 1, including a sleeve on said conduitslidable thereon to control the exposure of said gap.
 4. A system as setforth in claim 2, including a mesh applied to said conduit at said gap.5. A system as set forth in claim 1, wherein the size of said vent isadjustable.
 6. A system as set forth in claim 1, wherein said vent islocated no closer than approximately 10″ away from said restriction. 7.A system as set forth in claim 1, including an inside pipe in saidselected portion of the conduit spaced inwardly from said selectedportion to provide said restriction between said inside pipe and saidselected portion of the conduit.
 8. A system as set forth in claim 7,wherein: said selected portion of the conduit is substantiallycylindrical; and said inside pipe is substantially cylindrical and isgenerally concentric with said selected portion.
 9. A system as setforth in claim 8, wherein: said inside conduit has open upstream anddownstream ends and forms part of said path.
 10. A system as set forthin claim 9, wherein said downstream end of the inside conduit is spaceddownstream end of the inside conduit is spaced downstream from theconnection between said angled pipe and said conduit section.
 11. Asystem as set forth in claim 9, wherein: said conduit includes asubstantially cylindrical pipe adjacent to said conduit section andproviding an inlet thereto; said substantially cylindrical pipe has adiameter substantially equal to the diameter of said inside conduit; andsaid substantially cylindrical pipe has an end spaced upstream from theupstream end of said inside conduit.
 12. A system as set forth in claim7, wherein said vent comprises an adjustable gap in said conduitextending substantially continuously around the conduit.
 13. In apneumatic conveying system for flexible fabric items such as linens tobe laundered, the combination of: a conduit having an inlet forreceiving said items and an outlet for discharging said items, saidconduit having a flow path from said inlet to said outlet and includinga substantially straight conduit section; a venturi having an angledpipe jointing said conduit section at an acute angle and a restrictionin said conduit situated in proximity to a location at which said angledpipe joins said conduit section; a blower forcing air through saidangled pipe into said conduit to effect a low pressure area adjacentsaid restriction to draw said items through the conduit and a vent insaid conduit between said restriction and said outlet.
 14. A combinationas set forth in claim 13, wherein said vent comprises a gap in saidconduit and including a screen mesh covering said gap.
 15. A combinationas set forth in claim 14, including a sleeve on said conduit adjustablethereon to vary the exposure of said vent.
 16. A combination as setforth in claim 13, wherein the exposure of said vent is adjustable. 17.A method of conveying flexible fabric items such as table linens througha conduit, comprising the steps of: providing a venturi in said conduitat a selected location; forcing air into the conduit through saidventuri to effect a low pressure area in the conduit for drawing saidfabric items through the conduit; and venting some of the air from theconduit at a location downstream from said selected location.
 18. Amethod as set forth in claim 17, wherein the step of providing a venturiincludes providing an angled pipe connecting at an acute angle with saidconduit.
 19. A method as set forth in claim 18, wherein the step ofproviding a venturi includes providing a restriction in said conduit inproximity to a connection of said angled pipe with said conduit.
 20. Amethod as set forth in claim 19, wherein the step of providing arestriction includes providing an inside pipe in said conduit at alocation adjacent to the connection of said angled pipe with saidconduit.